Our new Biological Assessment is out - Klamath Basin Crisis

Part 6 OREGON SPOTTED FROGS
Oregon Spotted Frog (Rana pretiosa) is a candidate for listing under ESA.
Historically, the Oregon spotted frog ranged from British Columbia to the Pit
River drainage in northeastern California. Based on surveys of historical sites, the
Oregon spotted frog is now absent from at least 76 percent of its former range.
The majority of the remaining Oregon spotted frog populations are small and
isolated. These factors make the Oregon spotted frog more vulnerable than large,
connected populations to random, naturally occurring events, such as drought,
disease, and predation. (Federal Register: September 12, 2006)
The Spotted Frog can be found in the southwestern most parts of British
Columbia, and from the eastern side of the Puget/Willamette Valley Trough and
into the Columbia River Gorge Oregon and Southern Washington. The Oregon
Spotted Frog habitat historically covers Clackamas, Linn, Klamath, Multnomah,
Wasco, and Benton counties. Today the species has only been found to occur in
the Deschutes, Klamath, and Lane counties 45 .
Habitat of the Spotted Frog
Oregon Spotted Frog is an aquatic species found near recurrent bodies of water.
The Spotted Frog can be found in the shallows typically and prefers areas that
provide abundant floating aquatic plants. (Leonard et al. 1993, Corkran and
Thoms 1996, McAllister and Leonard 1997).
The Oregon Spotted Frogs habitats are identified by:
• Overwintering, Breeding sites are related by year-round water
• Reliable water levels that maintain depth between times of laying eggs
(oviposition) and species development (metamorphosis)
• Absence of predators, especially warm-water game fish and bullfrogs 46
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